2011-04-11_REPORT - C1980007 ‎(9)‎

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 4/11/2011
• Doc Name: 2010 Subsidence Report
• From: Wright Water Engineers, Inc
• To: DRMS
• Permit Index Doc Type: Subsidence Report
• Email Name: TAK
• Media Type: D
• Archive: No

Fall 2010 Subsidence and Geologic Field Observations
Box Canyon, Apache Rocks, and South. of Divide Mining Areas
is This location (E-seam overburden depth of 1,250 feet) continues to reveal cracks (Figure 1) that
are sub-parallel to the outer edge of the pad (likely resulting from differential settlement of the
rather large amount of fill placed at this location). A comparison photograph (Figure 2) taken
during the fall 2009 field visit shows what the pad had looked like after regrading on the
downhill side of the pad. Given that mining of the area occurred in late 2008 and early 2009, it is
likely that these reoccurring cracks are the result of differential settlement and/or instability of
the underlying materials.
Figure 1. Fall 2010 northeastward view of the MDW E1-48 drill pad (Location 1) at cracks in
the deepest fill which are sub-parallel to the outer edge of the pad.
831-032.792 Wright Water Engineers, Inc. Page 7
April 2011